Unusual gunpowder flask

[corrado26]

The first mark on the left probably is not the Tudor Rose, but the crown-mark of Sheffield. The listings found in the net show the silver hallmarks and I don't know wether these have been in use for brass too. So it is very uncertain to interpret their meaning.
The second mark from the left is certainly a "D", this and the next mark are unknown and the last one should be - if it were silver - the date letter "s", what in Sheffield stands for silver made in 1910. This date I think is very late, probably too late for the flask.